Stair structure



Patented Jan. 10, 1928.

UNITED STATES 1,655,769 PATENT OFFICE.

MORRIS LERNER, OF CHELSEA, MASSACHUSETTS, ASSIGNOR TO A. L. SMITH IRONVJ'ORKS, OF CHELSEA, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

STAIR STRUCTURE.

Application filed September 26, 1925. Serial No. 58,817.

.This invention pertains to stair structures and more particularly tostructures of that type in which forms made of sheet material, forexample, sheet steel, and each comprising a tread and a riser portion,are assembled to make the stair structure, the sheet metal treadportions of the forms usually supporting treads proper consisting ofconcrete, wood, rubber or the like which are clamped to or interlockedwith the form.

Commonly the tread and riser portion of the form are integrally unitedat the rear angle of the stair and adjacent forms are attached to oneanother by bolts, rivets or the 15 like at the forward angle or nosingof the stair.

' In order to provide a suitable pocket or receptacle for the concretefiller or other tread proper of the stair, it is customary to extend theupper part of the riser above the level of the tread of the next higherform so as to provide what may be termed a nosing flange, but while thedesired receptacle for the concrete tread is thus provided, the upwardlyextending nosing flange of the riser is a constantsour ce of annoyanceand danger since it is very difficult to anchor it rigidly in positionand as soon as the concrete begins to wear, this upwardly projectingnosing flange is exposed, constituting a menace to the safety of theuser. Since this nosing portion is subject to rapid wear it is desirablethat it may be replaced readily, but in the usual construction suchreplace ment of the nosing portion or the attachment of a wear plate atthis point is extremely diflicult since the space immediately to therear of the nosing is completely filled with concrete which cannoteasily be drilled and which will not hold screw threads.

The riser supports the load applied to the rear part of the next treadbelow and the connections uniting it to the next tread above are thuscalled upon to sustain this load. Since in the usual construction thesecon nections are relatively few in number the riser frequently pullsaway from the tread next above to such an extent as to elevate thenosing flange of the riser above the level of the concrete surface andto produce cracks in the concrete adjacent to the nosing.

Moreover, with usual constructions two or more workmenare required toassemble the stair forms and in some arrangements van aasiliaryarrangements in additioiit i the tread and risers must be prepared,carried in' stock by. the manufacturer, and htandled by the workmen inassembling the s am The principal object of the present invention is toprovide a stair structure having great strength and durability and inwhich the nosing of the stair is unusually strong and wear resistant,provides additional stiflness to the stair structure as a whole, and iscapable of ready renewal when worn; to provide a structure wherein thetread and riser are integrally united at the nosingso that the tread andriser cannot separate at this point; to provide a structure whereinample provision is made for interlocking the concrete or other treadproper with the metal parts and wherein wear of the concrete will notexpose dangerously sharp portions of the metal sub-structure; to providea structure of such character as to permit ready assemblage of the partsby a single workman; and to provide a form having a riser of greatstrength, considering the material employed and which is adapted to forma sanitary angle with the treads next below.

In the accompanying drawings in which a preferred embodiment of theinvention is illustrated, by way of example:

Fig. 1 is a longitudinal sectional View of a portion of a staircaseembodying this invention;

Fig. 2 is asection on the line 22 of Fig. 1;

Fig. 3 is a perspective view of a portion of one of the improved stairforms;

Fig. 4 is a view similar to Fig. 1 showing a modification of theinvention;

Fig. 5 is a section on the line 5-5 of Fig. 4;

Fig. 6 is a view similar to Fig. 1 showing stilil another modificationof the invention; an

Fig. 7 is a fragmentary vertical section to large scale showing theapplication of a wear plate to the nosing.

Referring now to the drawings in detail, 1 denotes stringers consistingof channels to which are bolted or otherwise fastened angle irons orcarriers 2. These angle irons form the immediate supporting means forthe stair forms 3.

Each form 3 comprises a riser portion 4 and a tread portion 5 integraltherewith. Atthe juncture of the riser and trad I pro ride a nosing 7 ofsubstantially U or channel shape. Thisnosing rises appreciably above thelevel of the tread and the rear wall 8 of the nosing preferably inclinesdownwardly and forwardly so that the nosing and tread meetin an acuteangle. The rear edge portion 9 of the tread is bent upwardly andforwardly to form an angle, preferably acute,

. with the main body of the tread. The lower 'with the holes 13 and 1 1alined.

other fastening means passes through each pair ofthese holes and alsothrough the angle iron 2 supporting the tread.

'l'i hen the forms are assembled,concrete I 15 is placed upon thetreads. The parts 8 of the nosing and 11 of the riser together with thetread form a pocket or mould trapezoidal in front to rear section forthe reception of th'e'concrete, and the concrete when set is locked inplace by reason of the upward convergence of parts 8 and 11. As will beseen in Fig. 1, the rearward slope of part 10 provides an obtuse anglebetween the concrete surface and the riser and this makes for increasedsanitation since the stairs are easier to clean and there are no cracksfor the'dirt to collect/in. 7 I

The arrangement thus far described provides a stair whose metal partsare integrally connected at the nosing so that there is no possibilityof their pulling-away from each other with consequent exposure of edgeswhich may be dangerous to the user, whileat the same time furnishing amaximum strength at'the point where it is most desired; Moreover sincethe flange 9 of the tread is disposed at-the rear side of the lower part11 of the next'riser, the latter is locked in "position so that itcannot be driven rear wardly by the impact of the feet of the user andthe stair is greatly strengthened in a front to rear direction by thishook-like interengagement of the parts. Moreover,

the shape of the stair form is such that the concrete tread is firmlylocked in position, while the double angle at the'lower part of theriser furnishes great strength in a transverse direction.

The provision of the hollow channel-like nosing has a further advantagein addition to those which have heretofore been men tioned. Asillustrated in Fi 7 a wear plate 30 may be secured to the top surface 7of the nosing when the nosing becomes worn through long use. This wearplate may readily be secured in position by means of screws 31 passingdown through threaded holes drilled in the upper member 7 of the nosing.As'the chamber 32 within the nosing is empty it is an easy matter todrill these holes and to tap them for the reception of the screws,whereas if the nosing overlay theconcrete tread such drilling andtapping would be a difficult and unsatisfactory operation- The wear plat230 may, as shown, cover merely the top edge of the nosing or may haveanextension upon its front edge overlapping the upper part of the riser.Figs. 1 and 5 illustrates novel form of angle iron which facilitates theassembly of the stairs. This angle iron '16 is notched in its upper orhorizontal, flange and the metal from these notches is bentperpendicular to the horizontal flange of the angle'to form locking lugs17 preferably of wedge-like form. These lugs areapertured as at'18 toreceive locking wedge pins.19.: The lug s'l'i pass up through the holes13. and let in the assembled stair formsl and the wedgepins 19 areinserted in the apertures 18 to lock the forms to' the angle irons andto each other. 1

The great advantage in this type of angle iron'lies in the fact that itrequires but one man to assemble the stairswhereas in the constructionshownin Figs. 1 to 3, it requires two men, one to manipulate the boltand another the nut. i lViththisimproved angle iron all that isnecessaryis to aline'the holes with the locking lugs and insert thewedge pins. i

In Figs. l and Gareshown two slightly modified types of stair forms- Inboth of these modifications the-bent-up portion-f the tread, as.hereinbefore described,- is eliminated, the tread terminating in ahorizontal plane. fin-Fig. 1 the rear of the tread is slightlyelevated-asat 20 so that the horizontal' portion 12 of the riser may bereceived between the tread and the corresponding angle iron or carrier2In Fig.

6 the rear end of the carrier or angle iron 2 is depressed'as at 21 soas to receive the horizontal portion 12- of the riser between it and thetread. In both of these modifica= tions the tread is supported upontheriser. It will be observed that by eliminating the portion 9 a savingin material iseffeeted without asacrifice of strength. \Vhile the lugs18 are herein shown as integral with the angle iron, they mayobviouslybe made as separate elements and suitably secured to theangles.

I claim: 7

1. A stair structure-comprising a riser, a nosing of double thickness, atread portion. integral with the riser, said nosing extending upwardlyabove the tread portion and'having its rear wall inclined forwardlylilil lll) and downwardly and the lower portion of the riser beinginclined baclrwardly and downwardly whereby a cementitious filler pouredupon the tread portion will tend to be locked in place by the rear wallof the nosing.

2. In a stair structure, a plurality of stair forms each comprising asubstantially channel-shaped nosing, and a riser and tread integraltherewith, the rear wall of said nosing inclining forwardly anddownwardly, the riser having a substantially horizontal flange at itslower part and a forwardly and upwardly inclined port-ion adjacent tosaid flange, whereby when said stair forms are assembled, the tread andforwardly inclined wall of the nosing of one form together with theforwardly inclined portion of the riser of the form nextabove provide apocket for the reception of a plastic filler, said pocket positivelylocking said filler to the first named form.

3. In a stair structure, stringers, carriers fastened to said stringers,and stair forms each comprising a tread and a riser, each riser having aforwardly directed flange at its lower edge, each tread being supportedupon a carrier and having its rear margin slightly elevated to provide aspace between said thread and its carrier for the reception of theforwardly directed flange on the riser.

4. In a stair structure, a carrier comprising an angle iron havingupstanding lugs on one of its flanges, said lugs being provided withapertures for the reception of locking pins.

5. A stair structure comprising a carrier having a horizontal supportingmember, a lug projecting upwardly from said supporting member, said lugbeing a transverse aperture, a pair of stair forms, each form having apart resting upon said supporting member, said parts having alignedapertures for the passage of the lug, and a wedge pin passing throughthe aperture in the lug and thereby locking the forms to the carrier.

Signed by me at- Boston, Massachusetts, this 24th day of September,1925.

MORRIS LERNER.

